We’re on pace for 4°C of global warming. Here’s why that terrifies the World Bank.
Posted by Brad Plumer
on November 19, 2012 at 11:28 am

Over the years at the U.N. climate talks, the goal has been to keep future global warming below 2°C. But as those talks have faltered, emissions have kept rising, and that 2°C goal is now looking increasingly out of reach. Lately, the conversation has shifted toward how to deal with 3°C of warming. Or 4°C. Or potentially more.

And that topic has made a lot of people awfully nervous. Case in point: The World Bank just commissioned an analysis (pdf) by scientists at the Potsdam Institute looking at the consequences of a 4°C rise in global temperatures above pre-industrial levels by 2100. And the report appears to have unnerved many bank officials. “The latest predictions on climate change should shock us into action,” wrote World Bank President Jim Yong Kim in an op-ed after the report was released Monday.

So what exactly has got the World Bank so worried? Partly it’s the prospect that a 4°C world could prove difficult—perhaps impossible—for many poorer countries to adapt to. Let’s take a closer look at the report:

1) The world is currently on pace for around 3°C to 4°C of global warming by the end of the century. In recent years, a number of nations have promised to cut their carbon emissions. The United States and Europe are even on pace to meet their goals. But those modest efforts can only do so much, especially as emissions in China and India keep rising. Even if all current pledges get carried out, the report notes, ”the world [is] on a trajectory for a global mean warming of well over 3°C.” And current climate models still suggest a 20 percent chance of 4°C warming in this emissions scenario.

2) The direct consequences of a 4°C rise in global temperatures could be stark. Four degrees may not sound like much. But, the report points out, the world was only about 4°C to 7°C cooler, on average, during the last ice age, when large parts of Europe and the United States was covered by glaciers. Warming the planet up in the opposite direction could bring similarly drastic changes, such as three feet or more of sea-level rise by 2100, more severe heat waves, and regional extinction of coral reef ecosystems.

3) Climate change would likely hit poorer countries hardest. The World Bank focuses on poverty reduction, so its climate report spends most of its time looking at how developing countries could struggle in a warmer world. For instance, a growingnumber of studies suggest that agricultural production could take a big hit under 3°C or 4°C of warming. Countries like Bangladesh, Egypt, Vietnam, and parts of Africa would also see large tracts of farmland made unusable by rising seas. “It seems clear,” the report concludes, “that climate change in a 4°C world could seriously undermine poverty alleviation in many regions.”

4) Yet the effects of 4°C warming haven’t been fully assessed — they could, potentially, be more drastic than expected. Perhaps the most notable bit of the World Bank report is its discussion of the limits of current climate forecasts. Many models, it notes, make predictions in a fairly linear fashion, expecting the impacts of 4°C of warming to be roughly twice as severe as those from 2°C of warming. But this could prove to be wrong. Different effects could combine together in unexpected ways:

Quote:

For example, nonlinear temperature effects on crops are likely to be extremely relevant as the world warms to 2°C and above. However, most of our current crop models do not yet fully account for this effect, or for the potential increased ranges of variability (for example, extreme temperatures, new invading pests and diseases, abrupt shifts in critical climate factors that have large impacts on yields and/or quality of grains).

What’s more, the report points out that there are large gaps in our understanding of what 4°C of warming might bring: “For instance,” it notes, “there has not been a study published in the scientific literature on the full ecological, human, and economic consequences of a collapse of coral reef ecosystems.”

5) Some countries might not be able to adapt to a 4°C world. At the moment, the World Bank helps many poorer countries build the necessary infrastructure to adapt to a warmer world. That includes dams and seawalls, crop research, freshwater management, and so forth. But, as a recent internal review found, most of these World Bank efforts are focused on relatively small increases in temperature.

This new World Bank report is less sure how to prepare for a 4°C world. “[G]iven that uncertainty remains about the full nature and scale of impacts, there is also no certainty that adaptation to a 4°C world is possible.” That’s why, the report concludes, “The projected 4°C warming simply must not be allowed to occur — the heat must be turned down. Only early, cooperative, international actions can make that happen.”

So what sorts of actions might that entail? The International Energy Agency recently offered its own set of ideas for curbing greenhouse-gas emissions and keeping future warming below 2°C. That included everything from boosting renewable energy to redesigning the world’s transportation system. But so far, nations have only made small progress on most of these steps.

Furthermore, I never said that govt had no role in protecting rights of the people to free from harm such as pollution. It just depends how it's done, such as common law strict liability. Places that don't have natural rights including property rights, in therefore don't have the same kind of legal system suffer from more pollution. What they suffer from is the tragedy of the commons—probably the model you have in mind.

So it is a documented fact that that hospital admissions and emergency room visits for respiratory problems increase on days when air pollution is worse.

Contributors to air pollution number in the millions, if you consider individual automobiles.

Are you suggesting that we get rid of all regulations and if I incur a hospital bill for an air pollution related incident that I should file millions of lawsuits for fractions of a penny for each individual that contributed to the problem?

Stuff that the average American can do (like not drive) simply won't happen. Ever. It's going to be damn near impossible to get Americans of all lifestyles and urban/rural environments to be able to use public transportation effectively. Not to mention the cost of building that kind of stuff.

It seems to be a common belief that there is no scientific consensus on the subject of climate change.

This is unequivocally not true. There is debate about how fast the climate is changing, there is debate about how it is changing and how it will change, there is debate about how this will affect the Earth's ecosystems and there is debate about how much of it is caused by human beings.

There is almost complete consensus in the scientific community that the climate is changing, and that at least part of that is anthropogenic.

These numbers are from Dr. James Powell. In his own words, he "searched the Web of Science, an online science publication tool, for peer-reviewed scientific articles published between January first 1991 and November 9th 2012 that have the keyword phrases “global warming” or “global climate change.” The search produced 13,950 articles.

OK, let's pretend for a second that man-made CO2 output has a significant impact on raising the Earth's temperature.

Let's also assume we are "due" for another ice age... (plenty of debate on this but since we are making wild leaps of faith on the first point, let's do the same here)

Would you would rather cut CO2 emissions NOW and have 100-500 years of "perfect" climate but suffer a catastrophic ice age or would you be willing to suffer 100-500 years of global warming and effectively stave off an ice age entirely?

It will be the height of irony if the effect of us curbing global warming is that we lose the opportunity to avoid mass extinction.

Of course, all of this is wild conjecture based on incomplete data and suspect models... which makes it a perfect fit for any discussion about climate change.

(btw we'll just ignore solar activity because , well, that seems to be an ok thing to do in many climate discussions)

Would you would rather cut CO2 emissions NOW and have 100-500 years of "perfect" climate but suffer a catastrophic ice age or would you be willing to suffer 100-500 years of global warming and effectively stave off an ice age entirely?

It seems to be a common belief that there is no scientific consensus on the subject of climate change.

This is unequivocally not true. There is debate about how fast the climate is changing, there is debate about how it is changing and how it will change, there is debate about how this will affect the Earth's ecosystems and there is debate about how much of it is caused by human beings.

There is almost complete consensus in the scientific community that the climate is changing, and that at least part of that is anthropogenic.

These numbers are from Dr. James Powell. In his own words, he "searched the Web of Science, an online science publication tool, for peer-reviewed scientific articles published between January first 1991 and November 9th 2012 that have the keyword phrases “global warming” or “global climate change.” The search produced 13,950 articles.

These are peer-reviewed scientific articles too. Not bullshit political spin.

First of all, I don't think that's a common belief at all. The people who don't understand that climate is always changing aren't really relevant to this debate.

Your argument kind of eats itself into nothing. OK, there might be a few people out there who think the climate is fixed and they're clearly wrong. Very few climate change skeptics have ever tried to argue that. Winning the argument over whether the climate is changing is nothing if you don't know how much it's changing, what the implications of that change are, what we can do to control it, or how much it would cost us.

__________________

“The American people are tired of liars and people who pretend to be something they’re not.” - Hillary Clinton

If we want to instead ONLY use empirical data than we should instead just admit that we don't know crap right now and we need to do a lot more research before we use our jump to conclusions mats.

Good to see you back with your "nobody knows anything", "empirical analyses are merely entertainment" bent.

__________________
That rabbit is crazy; I'm Brian Waters!

Kotter: "You are lucky I'm truly not the vindictive or psycho type...I'd be careful from now on, and I'd just back the hell off if I were you....otherwise, the Mizzou "extension office" life might get exciting"

To what extent do you wish to research? Do you wish to wait until the end of the earth as we know it for acceptable confirmation or is there another plateau you would find acceptable?

Happy Thanksgiving.

Happy Thanksgiving to you too!

I want a ton of research, I'm all for spending the money on getting to a more complete understanding of the climate and all factors involved. As to your Henny Penny statement... I can show far far far far more accepted theories regarding a coming ice age .. so do YOU want to just ignore global cooling and enjoy the next few centuries without addressing it? Seems awfully short sighted of you!

Fact is... an ice age would be far and away more catastrophic to human life than a warm period of even 10C warmer. If we are all concerned about theoretical futures... why is this so conveniently ignored?

Good to see you back with your "nobody knows anything", "empirical analyses are merely entertainment" bent.

No, I am all about accurate empirical analysis. When you conveniently leave out or minimize things like solar activity and cherry pick data sets and rely on shortcuts in your models... you aren't engaged in proper empirical analysis of any kind.

In engineering and science, we aren't allowed to make assumptions or guesses and pass them off as facts. I would wager that most respected climatologists don't. (I have read many reports that said one thing and then read "summaries" that completely lie about them, unfortunately it happens all the ****ing time these days and not just in regards to climate science.) The media and people like Direckshun misinterpret and misrepresent their work to push their own agendas. That is what bothers me the most.